Heterobilayer Ferroelectricity with Competitive Polarization

Two-dimensional ferroelectrics with large out-of-plane polarization (OOP) are promising for the design of low-power memory and logic devices, but their experimental realization remains limited due to the scarcity of homobilayers and the complexity of heterobilayers. Here, we perform high-throughput screening of 24,960 configurations and identify 43 semiconducting heterobilayer ferroelectrics with an OOP exceeding the experimentally reported value in MoS2/WS2 while maintaining sliding barriers below 100 meV/f.u. Among them, CdO/InN exhibits an OOP nearly 50 times greater than that of MoS2/WS2, along with a low sliding barrier of around 35 meV/f.u., making it a candidate that combines strong polarization with low-energy switching. The data analysis shows that heterobilayers composed of single-atom-layer monolayers mostly exhibit enhanced sliding ferroelectric behavior, providing a library of ferroelectrics. In addition, we develop a multiscale physical model that links monolayer characteristics to the sliding ferroelectric response by combining structural projection and polarization decomposition. This physical mechanism reveals a crucial competition between interlayer and intralayer dipoles in heterobilayer systems.